Sheet feeding mechanism for duplicating machines



Nov. 15, 1960 c. TROMBETTA SHEET FEEDING MECHANISM FOR DUPLICATINGMACHINES Filed Jan. 6. 1959 INVENTOR.

CARLO TPOMBETTA ATTORNEYS nited States SHEET FEEDING MECHANISM FORDUPLI- CATING MACHINES Carlo Trombetta, Caluso, Italy, assignor to lug.C. ()livetti 8: C., S.p.A., Ivrea, Italy, a corporation of Italy FiledJan. 6, 1959, Ser. No. 785,249

Claims priority, application Italy Jan. 8, 1958 7 Claims. (Cl. 271-62)This invention relates to the automatic sheet feeding mechanisms forcyclically operable duplicating machines. More specifically, the objectof the invention relates to an improved device for so raising the papertray as to bring the top sheet of the sheet pile to a predetermined,constant level before being fed during a machine cycle.

In the known devices the tray is usually moved upwards by anintermittently operated mechanism, such as a pawl and a ratchet wheelmechanism, whereby the sheet level will oscillate between twoconsecutive steps of said upward movement, each step being effected apredetermined number of machine cycles after the next preceding step.

An object of the invention is to provide a paper tray raising device forcyclically conditioning the sheet pile to bring the top sheet to .arigorously constant level before being fed.

Another object of the invention is to provide in such a device a bailfor positively setting during a portion of each machine the level ofsaid top sheet.

According to the invention in an automatic sheet feeding mechanism forcyclically operable duplicating machines, I now provide a device forconditioning the sheet pile to bring the top sheet to a constant levelbefore being fed, said device comprising a substantially verticallymovable tray for said pile, a spring urging said tray upwards, a bailcyclically operable for being set to a position arresting said pile atsaid level, and a locking member for said tray, said locking memberbeing operable concurrently with said bail to unlock said tray to enablesame to be moved by said spring until said pile is arrested by saidbail.

Further objects, features and advantages of the invention will becomeapparent from the following detailed description of a preferredembodiment thereof, taken in conjunction with the accompanying drawings,wherein:

Fig. l is a partial right-hand sectional view of a duplicating machinehaving an automatic sheet feeding device embodying the improvementsaccording to the invention;

Fig. 2 is a perspective view of a detail of Fig. 1.

With reference to Fig. 1, the numeral 3 indicates the conventionalmaster sheet supporting drum of the machine. The drum 3 is rotated by acyclically operable main shaft 4 which is also adapted to control byknown means the conventional sheet feeding rollers 6 and theconventional impression roller 5. During each machine cycle the feedingrollers 6 will feed the top sheet of the sheet pile 7 towards the drum3, whereas the impression roller will force the so-fed sheet against themaster sheet supported by the drum 3.

The sheet pile 7 is supported by a tray 8 which will be progressivelyraised to bring the top sheet to an operating position with respect tothe rollers 6.

According to a feature of the invention the tray 8 is carried by alinkage comprising an arm 10 pivoted on a stationary pin 50 of themachine frame 14 and provided with a pin 51 slidably mounted in ahorizontal slot 2,969,334 Patented Nov. 15, 1960 53 of the tray 8.Pivoted on the middle point of the arm 10 is a lever 11 having a pair ofarms each half as long as the pivoted arm 19. The free end of one arm ofthe lever 11 is provided with a pin 52 engaging a vertical slot of thetray 8; the free end of the other arm of said lever is provided with anelement or pin 12 slidably mounted in a slot 13 of the machine frame 14.The slot 13 is arranged according to a direction intersecting the pivot50 and inclined with respect to the straight line intersecting the pivot50 and the pin 52 an angle half as wide as the angle formed by the twoarms of the lever 11. In the drawings, said straight line is arrangedvertically, the angle formed by the two arms amounts to degrees, and theangle between the direction of the slot 13 and the vertical directionamounts to 45 degrees. The arm 10 is normally urged counterclockwise bya spring 9, whereby the tray 8 is urged upwards.

By inspecting the geometrical features and sizes of the arm 10 and lever11 it will be understood that a rotation of the lever 16 causes aparallel and rectilinear movement of the tray 8. More particularly, whenthe arm 16 is rotated counterclockwise the pin 51 will slide in thehorizontal slot 53 and the pin 12 of the lever 11 will be forced toobliquely move upwards along the inclined slot 13, while the pin 52 willmove vertically maintaining the tray 8 horizontal.

Secured to the main shaft 4 is a cam 15 co-operating with a cam follower17 of a lever 13 pivoted at 19. The lever 18 is urged clockwise by aspring 16 and carries a transverse bail 20 as long as the transversesize of the tray 8. During each cycle of the shaft 4, prior to the sheetfeeding action of the rollers 6, the portion 21 of the cam 15 rocks thelever 18 counterclockwise to positively set the bail 20 in the positionshown with broken lines in Fig. 1. This position of the bail 20determines a constant level wherefrom the top sheet of paper should befed to the drum 3 and at which the bail 20 is adapted to arrest thesheet pile 7 when the tray 8 is moved upwards, as will be hereinafterdescribed.

According to another feature of the invention, normally the pin 12 ofthe lever 11 contacts the edge of a locking member such as a spirallyshaped cam member 22 which thus normally locks the tray 7 against theurge of the spring 9. The cam member 22 is rockably mounted on a shaft23 secured to the machine frame 14. The axis of the shaft 23 isintersected by the aforesaid inclined direction of the slot 13. The pin12 results thus movable radially with respect to the shaft 23 and thecam member 22.

Integral with the cam member 22 is a hub 24 (Fig. 2) having connectedthereto an end of a flexible band 25. A spring 26 normally urges theband 25 upwards whereby the cam member 22 is urged to rockcounterclockwise to contact the pin 12. The spring 26 is so strong as toenable the cam member 22 to balance the upward thrust of the tray 8caused by the spring 9.

Furthermore, pivoted on the shaft 23 is a lever 27 having integraltherewith a hub 28. A helicoidal spring 29 is normally wound around thehub 28 and a portion of the hub 24. One end 31 of the spring 29 engagesa hole formed in a bent lug 32 of the lever 27, the other spring end 33contacts a projection 34 of a plate 35 secured to the shaft 23. Normallythe projection 34 anguare . larly forces the end 33 upwards to slightlyunwind the spring 29, whereby the cam member 22 is disconnected from thelever 27.

Integral with the lever 27 is a projection 36 (Fig. 1) adapted tocooperate with a pin 37 of a lever 38 pivoted on a stationary shaft 39.The lever 38 is provided with a cam follower 40 urged by a spring 41 tocontact the edge of a cam 42 secured to the main shaft 4. By the urge ofa spring 43 the lever 27 normally contacts a pin 44 of a crank-lever 45secured to a manipulative knob 46 shown with broken lines in Fig. 1.

The device operates as follows:

During each cycle of the main shaft 4, prior to the rightward feeding ofthe top sheet by the rollers 6 and concurrently with the operation ofthe bail 20 when being set in the constant level position shown 'bybroken lines in Fig. l, the cam 42 will rotate the lever 18counterclockwise. The pin 37 will thus engage the projection 36 and rockthe lever 27 clock-wise. The lug 32 of the lever 27 first winds up thespring 29 to rigidly connect the hub 24 with the hub 28 and then rocksthrough a certain angle the cam member 22 together with the lever 27,against the urge of the spring 26. The spiral edge of the cam member 22retracts from the pin 12 of the lever 11, thus unlocking the tray 8which is now raised by the spring until the sheet pile 7 is arrested bythe bail 20. Since the bail 20 is maintained in the set position by theportion 21 of the cam 15, in the corresponding portion of the machinecycle the level of the paper is positively set and the top sheet reachesa rigorously constant level before being fed by the feed rollers 6.

Thereupon the cam 42 enables the lever 38 to be returned to rest beforethe portion 21 of the cam 15 has left the lever 18. The lever 38 thusreleases the lever 27 which is restored by the spring 43, whereby thespring 29 is unwound and the hub 24 is disconnected from the hub 28. Thespring 26 may now rock the cam member 22 counterclockwise until its edgewill contact the pin 12. Concurrently the cam 15 enables the bail 20 tobe raised by the urge of the spring 16, the tray 8 being now locked bythe cam member 22 with the top sheet of the pile 7 occupying theconstant level position. Finally, the rollers 6 will be operated to feedthe top sheet rightwards, the pile 7 being now free from the bail 20.

When a new sheet pile is to be put on the tray 8, the latter may bemanually depressed against the urge of the spring 9. The pin 12 slidingin the inclined slot 13 moves away from the cam member 22. This latteris promptly rocked counterclockwise by the spring 26 until it contactsthe pin 12 once more to lock the tray 8 in its new position.

If it is now desired to manually raise the tray, the knob 46 may bemanually turned counterclockwise through a little angle. The pin 44 ofthe crank-lever 45 then rocks the lever 27 in a similar manner as doesthe pin 37, whereby the cam 22 will be rocked clockwise. By the urge ofthe spring 9 the tray 8 is now raised through an extent corresponding tosaid angle, irrespective of the cyclical operation of the machine,including the bail 20. If the knob 46 is turned repeatedly, the tray 8may be stepwise raised to any desired position, even higher than theconstant level position of the bail 20 shown by broken lines. However,in this case during the first ensuing cycle of the main shaft 4 the bail20 will positively push the tray 8 downwards against the urge of thespring 9, whereby the sheet pile 7 will bring the top sheet to theconstant level position.

From the above description it will be understood that if the cam member22 is rocked clockwise against the urge of the spring 26 either byoperation of the cam 42 or by hand, the pin 12 will follow the edge ofthe cam member 22 and the tray will be raised. On the contrary, if thetray 8 is manually moved downwards against the urge of the spring 9, thespring 26 will rock the cam member 22 counterclockwise until beingarrested by the pin 12. Therefore, the cam member 22 forms an adjustablelocking member for the tray 8.

It will be apparent that the frictional force generated by the movementof the pin 12 relatively to the edge of the cam member 22 enables thetwo springs 9' and 26 to remain mutually balanced irrespective of thevariable weight of the sheet pile 7.

The cam member '22 is provided with a projection 48 adapted to operate astop means, not shown in the draw ings, upon a full clockwise revolutionof the cam member 22, in order to automatically stop the duplicatingmachine when the sheet pile 7 is going to be exhausted.

It will be understood that many changes may be made in the aboveconstruction, and different embodiments of the invention could be madeWithout departing from the scope thereof. For example, to prevent thespring 29 from being excessively tensioned by the lug 32 whentransmitting rotation to the cam member 22, the lever 27 may be providedwith a projection, not shown in the drawings, which, after a few degreesof rotation winding up the spring 29 to rigidly connect the cam member22 with the lever 27, is adapted to push the spring end 33 upwardswhereby the further rotation of the lever 27 will merely bodily rotatethe spring 29 and the cam member 22.

What I claim is:

1. In an automatic sheet feeding mechanism for cyclically operableduplicating machines having a feeding member operable for engaging thetop sheet of the sheet pile to feed said top sheet, a device forconditioning the sheet pile to bring the top sheet to a constant levelbefore being fed, said device comprising a substantially verticallymovable tray for said pile, a spring urging said tray upwards, saidspring being sufiiciently strong to overcome the weight of the tray andthe sheet pile, a bail cyclically operable in timed relation with saidfeeding member for being positively set toa position arresting said pileat said level against the urge of said spring, and an undiscontinuedlocking member for locking said tray against the urge of said springirrespective of said sheet pile, said locking member being cyclicallyoperable concurrently with said bail to unlock said tray to enable sameto be moved by said spring until said pile is arrested by said bail.

2. In an automatic sheet feeding mechanism for cyclically operableduplicating machines having a feeding member operable for engaging thetop sheet of the sheet pile to feed said top sheet, a device forconditioning the sheet pile to bring the top sheet to a constant levelbefore being fed, said device comprising a substantially verticallymovable tray for said pile, a first spring urging said tray upwards saidfirst spring being sufiiciently strong to overcome the weight of thetray and the sheet pile, a bail cyclically operable in timed relationwith said feeding member for being positively set to a positionarresting said pile at said level against the urge of said first spring,an element connected with said tray, an undiscontinued cam shapedlocking member adapted to contact said element for locking said tray inany vertical position against the urge of said first spring irrespectiveof said sheet pile, a second spring normally urging said locking memberto contact said element, said second spring being so strong as to enablesaid locking member to balance the upward thrust of said tray, and meanscyclically operable concurrently with said bail to disable said secondspring, whereby said tray may be moved by said first spring until saidpile is arrested by said bail.

3. In an automatic sheet feeding mechanism for cyclically operableduplicating machines having a feeding member operable for engaging thetop sheet of the sheet pile to feed said top sheet, a device forconditioning the sheet pile to bring the top sheet to a constant levelbefore being fed, said device comprising a substantially verticallymovable tray for said pile, a first spring adapted to urge said trayupwards said first spring being sufficiently strong to overcome theweight. of the tray and the sheet pile, a bail cyclically operable intimed relation with said feeding member for being positively set to aposition arresting said pile at said level against the urge of saidfirst spring, an element connected with said tray, a spirally shapedrockable cam member adapted to contact said element for locking saidtray in any vertical position against the urge of said first springirrespective of said sheet pile, said element being radially movablewith respect to said locking member, a second spring normally urgingsaid locking member to so rock as to contact said element said secondspring being so strong as to enable said locking member to balance theupward thrust of said first spring, and means cyclically operableconcurrently with said bail for rocking said member against the urge ofsaid second spring to unlock said tray, whereby said tray may be movedby said first spring until said pile is arrested by said bail.

4. A device as defined in claim 3, characterized by manual means forrocking said locking member against the urge of said second spring toenable the tray to be moved upwards by said first spring irrespective ofthe cyclical operation of the machine.

5. In an automatic sheet feeding mechanism for cyclically operableduplicating machines, a device for conditioning the sheet pile to bringthe top sheet to a constant level before being fed, said devicecomprising a tray for said pile, a linkage for substantially verticallymoving said tray, said linkage being formed of a pivoted arm slidablyconnected with said tray and a lever pivoted on the middle point of saidpivoted arm and having a pair of arms each half as long as said pivotedarm, the free end of one arm of said lever being pivotally connected tosaid tray, the free end of the other arm of said lever being movable ina direction intersecting the pivot of said pivoted arm, a spring urgingsaid linkage upwards, and cyclically operable means in said device forarresting said pile at said level.

6. A device as defined in claim 5, wherein said means are formed of abail settable to a position arresting said pile at said level, anelement secured to the free end of said other arm, a spirally shapedrockable cam member adapted to contact said element for locking saidtray in any vertical position, said element being radially movable withrespect to said locking member, a second spring normally urging saidlocking member to so rock as to contact said element, said second springbeing so strong as to enable said locking member to balance said firstspring, and means operable concurrently with said bail for rocking saidmember against the urge of said second spring as to unlock said tray,whereby said tray may be moved by said first spring until said pile isarrested by said bail.

7. A device as defined in claim 5, characterized in that said directionis inclined with respect to the vertical direction an angle half as wideas the angle formed by the two arms of said pair.

Brasseur Feb. 5, 1935 Carroll Feb. 22, 1944

